1. Field of the Invention
The present invention relates to a primer reagent for amplifying an ALK fusion gene, an ALK fusion gene amplification reagent kit including the same, and an ALK fusion gene amplification method and ALK fusion gene analysis method using the same.
2. Description of Related Art
ALK (Anaplastic Limphoma Kinase) is one type of kinase. It is known that an ALK fusion gene is formed as a result of rearrangement or translocation of the ALK gene coding for ALK with another gene. The ALK fusion gene is known to be involved in lung cancer. Also, kinase inhibitors are effective as anticancer drugs for lung cancer in which the ALK fusion gene is involved. Thus, by analyzing whether the ALK gene in a patient is an ALK fusion gene or not, for example, the probability that the patient may have or develop lung cancer may be determined, or when the patient has lung cancer, as a treatment method, the use of a kinase inhibitor, the amount of the kinase inhibitor to be used, or changing of the kinase inhibitor to another therapeutic agent may be determined.
Examples of the ALK fusion gene include: EML4-ALK as a fusion gene with the EML4 (Echinoderm Microtubule-associated protein-Like 4) gene; KIF5B-ALK as a fusion gene with the KIF5B (Kinesin Family member 5B) gene; KLC1-ALK as a fusion gene with the KLC1 (Kinesin Light Chain 1) gene; and TFG-ALK as a fusion gene with the TFG gene (TRK-fused gene) (Patent Documents 1 to 4). Among them, variants V1, V2, V3a, V3b, and V6 of the EML4-ALK are seen in about 70% of lung cancer patients expressing the ALK fusion gene. Thus, simplifying the analysis process of these variants is useful in diagnosis and treatment of lung cancer.
A genetic testing method generally is carried out by, for example, causing nucleic acid amplification, such as PCR (Polymerase Chain Reaction), using a primer that anneals to a specific region in a target gene and determining the presence or absence of the target gene on the basis of whether or not the amplification occurred. When the target gene has a plurality of variants as described above, however, it requires cumbersome operations of providing primers for the respective variants to prepare reaction systems for the respective variants and checking the presence or absence of each one of the variants.